1. Technical Field
The present invention relates to a wireless communication, and more particularly, to a method of requesting radio resources for uplink packet transmission in wireless communication system.
2. Related Art
The GSM (Global System for Mobile communication) is a radio technology which has been developed as a system for standardizing radio communication systems in Europe and which has widely been deployed all over the world. The GPRS (General Packet Radio Service) is introduced to provide a packet switched data service in a circuit switched data service provided from the GSM. The EDGE (Enhanced Data Rate for GSM Evolution) employs the 8-PSK (Phase Shift Keying) instead of the GMSK (Gaussian Minimum Shift Keying) employed in the GSM. The EGPRS (Enhanced General Packet Radio Service) represents the GPRS using the EDGE.
In general, a downlink means a communication from a base station (BS) to a mobile station (MS) and an uplink means a communication from the MS to the BS.
In order for the MS to transmit packet data in the uplink, uplink radio resources should be assigned to the MS from the BS. In order to request the uplink radio resources, the MS firstly transmits a packet channel request message to the BSS. A series of processes of allowing the BS to assign radio resources to the MS is called a packet access procedure. While waiting for a response to the packet channel request message, the MS should monitor the entire PCCCH (Packet Common Control Channel) corresponding to its PCCCH_GROUP. Each PCCCH carries its own PCCCH_GROUP of the MSs. The MS in a specific PCCCH_GROUP listens for the response to the channel request message over the specific PCCCH to which the PCCCH_GROUP belongs, as described in 3GPP TS 05.02 V7.7.0 (2001-08), “Radio Access Network; Multiplexing and multiple access on the radio path”, section 6.5.6.
The BS (or network) may not respond to the packet channel request message from the MS. That is, the MS may not receive any response to the packet channel request message. This is called a random access failure. The random access failure results from various reasons such as a reason that the BS cannot receive the packet channel request message.
When there is such an error that the random access failure occurs in the course of performing the packet access procedure to assign the uplink radio resources, it is important by what method such an error should be processed. Since the error in the packet access procedure can always occur, an efficient method for processing such an error should be prepared. Otherwise, the assignment of the uplink radio resources may be delayed, thereby deteriorating the quality of the wireless communication system.